Method and apparatus for buffer status report in mobile communication system

ABSTRACT

Method for radio communication with base station, by user equipment (UE), apparatus in UE for radio communication with base station, a method for radio communication with a UE by a base station, and an apparatus in a base station for radio communication with a UE are provided. The method for radio communication with a base station, by a UE, includes identifying whether an uplink resource allocated for data transmission to the base station is available, in response to a buffer status report for transmission to the base station being triggered; transmitting an uplink packet including the buffer status report using the available uplink resource, in response to the uplink resource being available; and transmitting a scheduling request to the base station, in response to the UE not having an available uplink resource and a first timer being expired, wherein the first timer starts when the buffer status report is triggered.

PRIORITY

This continuation application claims priority under 35 U.S.C. § 120 toU.S. patent application Ser. No. 16/293,093, filed on Mar. 5, 2019 inthe United States Patent and Trademark Office (USPTO), which is acontinuation application of U.S. patent application Ser. No. 15/676,439,filed on Aug. 14, 2017 in the USPTO (now U.S. Pat. No. 10,225,822 issuedon Mar. 5, 2019), which is a continuation application of U.S. patentapplication Ser. No. 14/704,480, filed on May 5, 2015 in the USPTO (nowU.S. Pat. No. 9,736,818 issued on Aug. 15, 2017), which is acontinuation application of U.S. patent application Ser. No. 13/690,893,filed on Nov. 30, 2012 in the USPTO (now U.S. Pat. No. 9,025,444 issuedon May 5, 2015), which is a continuation application of U.S. patentapplication Ser. No. 12/515,115 (now abandoned), which was filed on May15, 2009 in the USPTO, and claims priority under 35 U.S.C. § 365 toInternational Application No. PCT/KR2007/005667, which was filed on Nov.12, 2007, and under 35 U.S.C. § 119(a) to Korean Patent Application No.10-2006-0113011, which was filed in the Korean Intellectual PropertyOffice on Nov. 15, 2006, the content of each of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to mobile communication systems, and moreparticularly to a method and an apparatus for periodically reporting thebuffer status in a mobile communication system.

2. Description of the Related Art

As generally known in the art, the LTE (Long Term Evolution), which isthe evolved mobile communication system of the third-generation mobilecommunication system of UMTS (Universal Mobile TelecommunicationService), provides a high-speed packet service based on the OFDM. In thecase of a mobile communication system in which the Node B dynamicallyallocates a transmission resource, such as LTE or EUDCH (Enhanced UplinkDedicate Channel), the UE must report the buffer status to, the Node Bprior to transmitting data through the uplink. Schemes for reporting thebuffer status include an event-triggered scheme in which a buffer statusreport message is transmitted if a specific condition is satisfied, anda periodic scheme in which a buffer status report message is transmittedat a predetermined cycle.

In the case of the EUDCH, both the event-triggered scheme and theperiodic scheme have been adopted. Both schemes are also expected to beemployed by the LTE.

FIG. 1 shows an exemplary scheme for periodically reporting the bufferstatus according to the prior art.

When such a periodic scheme is employed, the UE activates a timer aftercompleting the transmission of a buffer status report message. If thetimer expires, the UE transmits a new buffer status report message.

Referring to FIG. 1, if no transmission resource has been allocated tothe UE 105 when the timer has expired (115), the UE 105 transmits asignal for a scheduling request, for example, to the Node B 110 (120),which then is allocated a transmission resource for the buffer statusreport (125). The UE 105 then transmits a buffer status report messagebased on the allocated transmission resource (130).

On the other hand, if the UE 105 has a transmission resource allocatedthereto when the timer has expired (135), the UE 105 piggybacks thebuffer status report message onto the uplink data by using the allocatedtransmission resource, and transmits it.

In other words, if the UE is to transmit a buffer status report messagewith no transmission resource allocated thereto, the UE must transmit aseparate uplink signal to the Node B (120), and receive a downlinktransmission resource allocation signal from the Node B (125). If atransmission resource has been allocated (135), the UE can directlypiggyback and transmit an uplink signal, which includes a buffer statusreport message, without exchanging a separate control message fortransmitting the buffer status report message (140). As such, the bufferstatus report message is preferably transmitted after a transmissionresource has been allocated.

SUMMARY OF THE INVENTION

Accordingly, the present invention is designed to address at least theproblems and/or disadvantages described above and to provide at leastthe advantages described below.

An aspect of the present invention is to provide a method and anapparatus for periodically reporting the buffer status by a UE in such amanner that the buffer status report is conducted according to whetheror not a transmission resource can be allocated.

In accordance with an aspect of the present invention, a method isprovided for radio communication with a base station, by a UE. Themethod includes identifying whether an uplink resource allocated fordata transmission to the base station is available, in response to abuffer status report for transmission to the base station beingtriggered; transmitting an uplink packet including the buffer statusreport using the available uplink resource, in response to the uplinkresource being available; and transmitting a scheduling request to thebase station, in response to the UE not having an available uplinkresource and a first timer being expired, wherein the first timer startswhen the buffer status report is triggered.

In accordance with an aspect of the present invention, an apparatus in aUE for radio communication with a base station is provided. Theapparatus includes a controller configured to identify whether an uplinkresource allocated for data transmission to the base station isavailable, in response to a buffer status report for transmission to thebase station being triggered; and a transceiver configured to transmitan uplink packet including the buffer status report using the availableuplink resource in response to the uplink resource being available, and,otherwise, transmitting a scheduling request to the base station inresponse to the UE not having an available uplink resource and a firsttimer being expired, wherein the first timer starts when the bufferstatus report is triggered.

In accordance with an aspect of the present invention, a method forradio communication with a UE by a base station is provided. The methodincludes receiving an uplink packet including a buffer status reportfrom the UE using an uplink resource in response to the uplink resourceallocated for data reception being available for the UE; and receiving ascheduling request from the UE in response to an available uplinkresource not being allocated to the UE after a predetermined time afterthe buffer status report is triggered by the UE, wherein the schedulingrequest is received in response to the UE not having an available uplinkresource and a first timer being expired, and wherein the first timerstarts when the buffer status report is triggered.

In accordance with an aspect of the present invention, an apparatus in abase station for radio communication with a UE is provided. Theapparatus includes a receiver configured to receive an uplink packetincluding a buffer status report and a scheduling request from the UE;and a controller configured to allocate an uplink resource to the UE inresponse to the scheduling request, wherein the receiver is configuredto receive the uplink packet including the buffer status report from theUE using the uplink resource, in response to the uplink resourceallocated for data reception being available for the UE, and, thereceiver is configured to receive the scheduling request from the UE inresponse to an available uplink resource not being allocated to the UEafter a predetermined time after the buffer status report is triggeredby the UE, wherein the scheduling request is received in response to theUE not having an available uplink resource and a first timer beingexpired, and wherein the first timer starts when the buffer statusreport is triggered.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present invention will be more apparent from thefollowing detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a flowchart illustrating a scheme for periodically reportingthe buffer status according to the prior art;

FIG. 2 is a block diagram illustrating an LTE mobile communicationsystem;

FIG. 3 illustrates a protocol stack of an LTE mobile communicationsystem;

FIG. 4 is a flowchart illustrating an overall operation according to anembodiment of the present invention;

FIG. 5 is a flowchart illustrating an operation of a UE according to anembodiment of the present invention;

FIG. 6 is a flowchart illustrating an operation for setting a NodeB-estimated buffer status parameter by a UE according to an embodimentof the present invention;

FIG. 7 is a flowchart illustrating an operation for setting a NodeB-estimated buffer status parameter by a UE according to an embodimentof the present invention; and

FIG. 8 is a block diagram illustrating a UE device according to anembodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Various embodiments of the present invention will now be described indetail with reference to the accompanying drawings. In the followingdescription, specific details such as detailed configuration andcomponents are merely provided to assist the overall understanding ofthese embodiments of the present invention. Therefore, it should beapparent to those skilled in the art that various changes andmodifications of the embodiments described herein can be made withoutdeparting from the scope and spirit of the present invention. Inaddition, descriptions of well-known functions and constructions areomitted for clarity and conciseness.

According to an embodiment of the present invention, the UE periodicallyreports the buffer status to the Node B in the following manner: ifthere is a possibility that the Node B will allocate a transmissionresource to the UE in the near future, the UE stands by for apredetermined period of time and, if a transmission resource isallocated, transmits a buffer status report message. If there is nopossibility that the Node B will allocate a transmission resource to theUE, the UE transmits a buffer status report message as soon as a bufferstatus report is triggered. Therefore, even if the time to transmit abuffer status report message arrives while no transmission resource hasbeen allocated, a buffer status report message is transmitted after atransmission resource is allocated. This advantageously simplifies theprocedure for transmitting a buffer status report message.

It is to be noted that, although embodiments of the present inventionwill be described with reference to an LTE (Long Term Evolution) systemas an example, the present invention is not limited to it and isapplicable to any type of communication system.

The LTE system, to which the present invention is applied, will now bedescribed briefly prior to descriptions of embodiments of the presentinvention.

FIG. 2 shows an exemplary structure of an LTE mobile communicationsystem to which the present invention is applied.

Referring to FIG. 2, E-RANs (Evolved UMTS Radio Access Networks) 210 and212 have a simple two-node structure including evolved Node Bs(hereinafter, referred to as ENBs or Node Bs) 220, 222, 224, 226, and228 and anchor nodes 230 and 232. The UE (User Equipment) 201 accessesthe IP (Internet Protocol) network by means of the E-RANs 210 and 212.

The ENBs 220-228 correspond to existing Node Bs in the UMTS system, andare connected to the UE 201 via wireless channels. The ENBs 220-228aggregate information regarding the conditions of UE 201 and schedulesthe UE 201, and are in charge of functions regarding wireless resourcemanagement. The ENBs 220-228 are provided with a control protocol, suchas RRC (Radio Resource Control).

In order to realize a maximum transmission rate of 100 Mbps, the LTEemploys the OFDM (Orthogonal Frequency Division Multiplexing) as thewireless access technology in the 20 Mhz bandwidth. In addition, the LTEadopts an AMC (Adaptive Modulation& Coding) scheme, in which themodulation scheme and the channel coding ratio are determined accordingto the channel condition of the UE.

FIG. 3 shows a protocol stack of an LTE mobile communication system towhich the present invention is applied.

Referring to FIG. 3, PDCP (Packet Data Convergence Protocol) layers 305and 340 are adapted for compression/decompression andciphering/deciphering of IP headers. In RLC (Radio Link Control) layers310 and 335, a PDCP PDU (Packet Data Unit) is reconstructed to anappropriate size (hereinafter, a packet outputted from a specificprotocol entity is referred to as a PDU of the protocol), and thereconstructed packets are subjected to an ARQ (Automatic Repeat reQuest)operation. The PDCP layers 305 and 340 and the RLC layers 310 and 335constitute at least one PDCP entity (i.e. PDCP device) or at least oneRLC entity (i.e. RLC device), which can be constructed for each serviceor flow when communication begins, and process data packets by usingeach entity. As shown in FIG. 3, the PDCP layers 305 and 340 are locatedon the UE and the anchor node, respectively, and the RLC layers 310 and335 are located on the UE and the ENB, respectively.

MAC layers 315 and 330 are connected with various RLC entities, and areadapted to multiplex RLC PDUs into MAC PDUs and demultiplex MAC PDUsinto RLC PDUs.

Physical layers 320 and 325 are adapted to channel-code anchor layerdata (i.e. MAC PDUs), modulate them into OFDM symbols, and transmit themthrough wireless channels. In addition, the physical layers 320 and 325receive OFDM symbols via wireless channels, demodulate andchannel-decode them, and transfer them to the anchor layer.

The UE according to an embodiment of the present invention has a NodeB-estimated buffer status (hereinafter, referred to as EBS) parameter, afirst timer, and a second timer.

The EBS parameter corresponds to the buffer status of the UE asestimated by the Node B, and is managed by the UE. The EBS has a valuecorresponding to either “empty” or “non-empty”.

It means that, if the EBS is set to “empty”, the Node B regards that thebuffer of the UE is empty. Therefore, there is no possibility that theNode B will allocate a transmission resource to the UE unless the UEseparately reports the buffer status.

It means that, if the EBS is set to “non-empty”, the Node B regards thatdata is stored in the buffer of the UE. Therefore, there is apossibility that the Node B will allocate a transmission resource to theUE, even if the UE does not separately report the buffer status.

According to an embodiment of the present invention, the UE checks theEBS every time it has to make the periodic buffer status report, and, ifthe EBS is “non-empty”, the UE stands by for a predetermined period oftime without transmitting a buffer status report message. If the UE isallocated a transmission resource thereto for the period of time, the UEtransmits a buffer status report message to the Node B by using theallocated transmission resource. If the UE fails to be allocated atransmission resource until the period of time elapses, the UE isallocated a transmission resource for a buffer status report theretoaccording to a predetermined procedure (e.g. scheduling request) as inthe case of the prior art, and transmits a buffer status report messageby using the allocated transmission resource. On the other hand, if theEBS is “empty”, the UE is allocated a transmission resource for a bufferstatus report thereto according to a predetermined procedure with nostandby, and transmits a buffer status report message to the Node B byusing the allocated transmission resource.

For convenience of description, the procedure for transmitting a bufferstatus report message according to the present invention will now bedivided into two and described accordingly.

The first buffer status report message transmission procedure: it isused when there is no uplink transmission resource for piggybacking abuffer status report message. For example, the UE transmits a small-sizeuplink signal, such as a scheduling request, to the Node B, which thenis allocated a predetermined transmission resource in response of theuplink signal from the Node B. The allocated transmission resource isused to transmit a buffer status report message to the Node B.

The second buffer status report message transmission procedure: it isused when there is an uplink transmission resource for piggybacking abuffer status report message. The UE piggybacks a buffer status reportmessage onto uplink data and transmits it.

FIG. 4 shows the overall operation according to an embodiment of thepresent invention.

Referring to FIG. 4, a specific situation occurs at a point of time, inwhich the UE 405 must make a periodic buffer status report (415). Forexample, if the first timer that been activated after completelytransmitting the preceding buffer status report message expires, the UErecognizes that it must make a periodic buffer status report.

The UE checks the EBS at that point of time and, if the EBS correspondsto “non-empty”, determines that the Node B is likely to allocate atransmission resource to the UE in the near future. Then, the UEactivates the second timer and stands by without transmitting a bufferstatus report message in response (420).

If the Node B allocates a transmission resource to the UE before thesecond timer expires (425), the UE transmits a buffer status reportmessage to the Node B according to the above-mentioned second bufferstatus report message transmission procedure (430). In other words, theUE piggybacks a buffer stature report message onto data transmittedthrough the uplink, and transmits it. After the buffer status reportmessage has been completely transmitted, the UE activates the firsttimer to check the point of time to transmit the next periodic bufferstatus report message.

On the other hand, if the Node B fails to allocate a transmissionresource to the UE until the second timer expires (435), the UEtransmits a buffer status report message to the Node B according to theabove-mentioned first buffer status report message transmissionprocedure (440). Particularly, the UE transmits an uplink signal (e.g.scheduling request) through the uplink so that a transmission resourceis allocated. Then, the UE transmits a buffer status report message byusing the allocated transmission resource. After the buffer statusreport message has been completely transmitted, the UE activates thefirst timer to check the point of time to transmit the next periodicbuffer status report message (445).

If the first time expires and if the UE is supposed to proceed with aperiodic buffer stature report (450), the UE checks the EBS again. Ifthe EBS has been set to “empty” (455), i.e. if there is no possibilitythat a transmission resource will be allocated to the UE within apredetermined period of time, the UE transmits a buffer status reportmessage to the Node B according to the first buffer status reportmessage transmission procedure (460). Particularly, the UE transmits anuplink signal (e.g. scheduling request) so that a transmission resourceis allocated. Then, the UE transmits a buffer status report message byusing the allocated transmission resource. After the buffer statusreport message has been completely transmitted, the UE activates thefirst timer to check the point of time to transmit the next periodicbuffer status report message (465).

FIG. 5 shows the operation of the UE according to an embodiment of thepresent invention.

Referring to FIG. 5, if a buffer status report is triggered in step 505,the UE proceeds to step 510 and checks the EBS.

If the EBS corresponds to “empty”, the UE proceeds to step 515 andconducts the first buffer status report message transmission procedure.

In order to conduct the first buffer status report message transmissionprocedure, the UE transmits a scheduling request signal by using aphysical channel in order to request resource allocation fortransmitting a buffer status report in step 515. After a transmissionresource is allocated in step 520, the UE transmits a buffer statusreport message by using the allocated transmission request in step 525.Then, the UE activates the first timer for a periodic buffer statusreport in step 545.

On the other hand, if the EBS corresponds to “non-empty”, i.e. if thereis a possibility that the Node B will allocate a transmission resourceto the UE without a separate scheduling request of the UE, the UEproceeds to step 530 and activates the second timer in order to conductthe second buffer status report message transmission procedure.

If a transmission resource is allocated to the UE before the secondtimer expires, the UE proceeds to step 540. Then, the UE piggybacks abuffer status report message onto uplink data, which is transmittedbased on the allocated transmission resource, and transmits the bufferstatus report message. The UE then proceeds to step 545 and activatesthe first timer for a periodic buffer status report.

On the other hand, if no transmission resource is allocated until thesecond timer expires, the UE proceeds to step 515 and follows theabove-mentioned first buffer status report message transmissionprocedure.

The shorter the first timer is set for the periodic buffer statusreport, the more frequently the UE transmits a buffer status reportmessage, which results in unnecessary data transmission. If the firsttimer is set to be excessively long when the UE is executing adelay-sensitive service, the buffer status report message transmissionmay be delayed, which degrades the service quality. Therefore, the firsttimer is set based on consideration of the type of service executed bythe UE, the required service quality, etc.

Those skilled in the art can understand that, if the second timer hasbeen activated, the Node B is aware of the fact that there is uplinkdata to be transmitted from the buffer of the UE. Therefore, as long asthe Node B has a transmission resource to allocate, the Node B willallocate it to the UE. However, if the UE presumes the Node B to beaware of the fact that the UE has transmission data while the Node Bactually considers that the UE has no transmission data, the Node B willallocate no transmission resource no matter how long the UE may wait. Inorder to prevent the UE from waiting forever in such a situation, thepresent invention proposes that the second timer be used. Consideringthat such an erroneous situation rarely occurs in a normal network, thesecond timer preferably has a sufficiently large setup value.

As mentioned above, the EBS is a parameter for storing a valuecorresponding to an estimation made by the UE regarding how the Node Bwill recognize the buffer condition of the UE.

In order to ensure that the EBS has a value reflecting the accuratebuffer condition of the UE as recognized by the Node B, the UE transmitsthe last data together with a “last data indicator” according to thepresent invention. If the Node B receives data containing a last dataindicator from the UE, the Node B recognizes that there is no more datastored in the buffer of the UE. After the data containing the last dataindicator has been completely transmitted, the UE sets the EBS to“empty”.

It is to be noted that the UE uses all transmission resources allocatedby the Node B. It means that, if a padding has been inserted into datatransmitted by the UE, the UE has no more data to transmit. Therefore,the last data indicator may be replaced with a padding. Moreparticularly, if the UE has a sufficient amount of allocatedtransmission resources so that it can insert a padding into the lastdata, the last data indicator is not necessarily inserted because thepadding acts as the last data indicator. Therefore, if the Node Breceives data containing a padding, the Node B determines that thecorresponding UE has no data, even if no last data indicator has beenfound to be inserted therein.

FIG. 6 shows a detailed process for setting the EBS by the UE.

Referring to FIG. 6, as the UE 605 switches from an idle state to aconnected state, the UE initializes the EBS as “empty” (615), andtransmits the first buffer status report message to the Node B 610(620). After the UE 605 is allocated a transmission resource from theNode B 610 (625), the UE 605 sets the EBS to “non-empty” (630), andtransmits uplink data by using the allocated transmission resource(635).

If the time comes to transmit the last data stored in the buffer whilethe EBS has been set to “non-empty” (645), the UE 605 piggybacks a lastdata indicator into the last data and transmits them together (650).After the data containing the last data indicator has been completelytransmitted, the UE 605 sets the EBS to “empty” (655).

FIG. 7 is a flowchart showing a process for setting the EBS by the UE.

Referring to FIG. 7, the UE initializes the EBS as “empty” when itinitially switches from an initial state to a connected state (705). Ifa transmission resource is allocated to the UE while the EBS has beenset to “empty” (710), the UE sets the EBS to “non-empty” (715). The UEmaintains the EBS as “non-empty” until the data containing the last dataindicator has been completely transmitted. If the data containing thelast data indicator has been completely transmitted (720), the UEinitializes the EBS as “empty” again (705). The UE repeats thisoperation.

Although an embodiment of the present invention has been described on anassumption that the buffer status report is triggered periodically, thepresent invention is not limited to that assumption and is applicable toa case, for example, in which the buffer stature report is triggered inresponse to a specific event. More particularly, according to thepresent invention, when a buffer status report that has been set to begenerated periodically is triggered, the UE checks the EBS and, if theEBS is “non-empty”, activates the second timer. If the UE is allocatedan uplink transmission resource from the Node B before the second timerexpires, the UE transmits a buffer status report by using the allocateduplink transmission resource.

As such, the present invention can be summarized as follows: if there isa possibility that the Node B will allocate a transmission resource tothe UE within a short period of time after a buffer status report istriggered, the explicit transmission resource request process of the UEbased on buffer status report message transmission, for example, isdelayed. This operation is not limited to the periodic buffer statusreport, and is applicable to a buffer status report triggered by anon-periodic event. For example, assuming that a buffer status reporthas been triggered by the generating of data having a priority higherthan that of data currently stored in the UE, the UE checks the EBS and,if the EBS is “non-empty”, activates the second timer. The UE transmitsno buffer status report message as long as the second timer is working,but waits for the Node B to allocate a transmission resource to the UEaccording to a predetermined scheduling operation. Those skilled in theart can easily understand that, if no transmission resource is allocateduntil the second timer expires, the UE transmits buffer status reportmessage to explicitly request the Node B to be allocated a transmissionresource.

FIG. 8 is a block diagram showing a UE device according to an embodimentof the present invention.

Referring to FIG. 8, the UE according to an embodiment of the presentinvention includes a transmission buffer 805, a buffer status reportcontroller 810, a transmission resource allocation request unit 815, atransmission controller 820, a multiplexer 825, and a transceiver 830.

The transmission buffer 805 stores anchor layer data, and transmits datato the multiplexer 825 under the control of the transmission controller820.

The buffer status report controller 810 generates a buffer status reportmessages if a predetermined condition is satisfied, and transfers it tothe multiplexer 825. The buffer status report messages containsinformation including the amount of data stored in the transmissionbuffer 805, the priority, etc.

The buffer status report controller 810 manages the EBS, and activatesthe first timer to be informed of the time to periodically provide abuffer status report message. If the time for periodic reporting hasarrived, the buffer status report controller 810 checks the EBS anddecides whether or not to activate the second timer. Particularly, thebuffer status report controller 810 activates the second timer if theEBS is “non-empty”. If a transmission resource is allocated before thesecond timer expires, the buffer status report controller 810 generatesa buffer status report message and transfers it to the multiplexer 825so that it is transmitted together with data by using the allocatedtransmission resource.

If the EBS is “empty” or if no transmission resource is allocated untilthe second timer expires while the EBS is “non-empty”, the buffer statusreport controller 810 instructs the transmission resource allocationrequest unit 815 to transmit a transmission resource allocation requestsignal. After a transmission resource is allocated, the buffer statusreport controller 810 generates a buffer status report message andtransfers it to the multiplexer 825.

At the request of the buffer status report controller 810, thetransmission resource allocation request unit 815 transmits atransmission resource allocation request signal to the Node B via thetransceiver 830 by using uplink transmission resources according to apredetermined procedure.

The transmission controller 820 receives a downlink control channel viathe transceiver 830 and checks if there is an allocated transmissionresource. If so, the transmission controller 820 instructs thetransmission buffer 805 or the buffer status report controller 810 totransfer data to the multiplexer 825.

The multiplexer 825 multiplexes the data, which has been transferred bythe transmission buffer 805 or the buffer status report controller 810,into a single packet and transmits it to the transceiver 830.

The transceiver 830 transmits the packet, which has been transferred bythe multiplexer 825, via a wireless channel; it transmits a signal,which has been transferred by the transmission resource allocationrequest unit 815, via the wireless channel; and it transfers a downlinkcontrol channel signal, which has been received via the wirelesschannel, to the transmission controller 820.

While the present invention has been shown and described with referenceto certain embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the invention as definedby the appended claims.

What is claimed is:
 1. A method for radio communication with a basestation, by a user equipment (UE), the method comprising: identifyingwhether an uplink resource allocated for data transmission to the basestation is available, in response to a buffer status report fortransmission to the base station being triggered; transmitting an uplinkpacket including the buffer status report using the available uplinkresource, in response to the uplink resource being available; andtransmitting a scheduling request to the base station, in response tothe UE not having an available uplink resource and a first timer beingexpired, wherein the first timer starts when the buffer status report istriggered.
 2. The method of claim 1, further comprising starting, aftertransmitting the uplink packet including the buffer status report, asecond timer for a periodic buffer status report.
 3. The method of claim2, wherein the buffer status report is triggered whenever the secondtimer expires.
 4. The method of claim 1, wherein the buffer statusreport is triggered when there is no data to be transmitted by the UE tothe base station.
 5. An apparatus in a user equipment (UE) for radiocommunication with a base station, the apparatus comprising: acontroller configured to identify whether an uplink resource allocatedfor data transmission to the base station is available, in response to abuffer status report for transmission to the base station beingtriggered; and a transceiver configured to transmit an uplink packetincluding the buffer status report using the available uplink resourcein response to the uplink resource being available, and, otherwise,transmitting a scheduling request to the base station in response to theUE not having an available uplink resource and a first timer beingexpired, wherein the first timer starts when the buffer status report istriggered.
 6. The apparatus of claim 5, wherein the controller isfurther configured to start, after transmitting the uplink packetincluding the buffer status report, a second timer for a periodic bufferstatus report.
 7. The apparatus of claim 6, wherein the controller isfurther configured to trigger the buffer status report whenever thesecond timer expires.
 8. The apparatus of claim 6, wherein the bufferstatus report is triggered when there is no data to be transmitted bythe UE to the base station.
 9. A method for radio communication with auser equipment (UE) by a base station, the method comprising: receivingan uplink packet including a buffer status report from the UE using anuplink resource in response to the uplink resource allocated for datareception being available for the UE; and receiving a scheduling requestfrom the UE in response to an available uplink resource not beingallocated to the UE after a predetermined time after the buffer statusreport is triggered by the UE, wherein the scheduling request isreceived in response to the UE not having an available uplink resourceand a first timer being expired, and wherein the first timer starts whenthe buffer status report is triggered.
 10. The method of claim 9,wherein the buffer status report is triggered whenever a second timerfor a periodic buffer status report expires, and the second timer startsafter transmitting the buffer status report.
 11. The method of claim 9,wherein the buffer status report is triggered when there is no data tobe transmitted by the UE to the base station.
 12. An apparatus in a basestation for radio communication with a user equipment (UE), theapparatus comprising: a receiver configured to receive an uplink packetincluding a buffer status report and a scheduling request from the UE;and a controller configured to allocate an uplink resource to the UE inresponse to the scheduling request, wherein the receiver is configuredto receive the uplink packet including the buffer status report from theUE using the uplink resource, in response to the uplink resourceallocated for data reception being available for the UE, and, thereceiver is configured to receive the scheduling request from the UE inresponse to an available uplink resource not being allocated to the UEafter a predetermined time after the buffer status report is triggeredby the UE, wherein the scheduling request is received in response to theUE not having an available uplink resource and a first timer beingexpired, and wherein the first timer starts when the buffer statusreport is triggered.
 13. The apparatus of claim 12, wherein the bufferstatus report is triggered whenever a second timer for a periodic bufferstatus report expires, and the second timer starts after transmittingthe buffer status report.
 14. The apparatus of claim 12, wherein thebuffer status report is triggered when there is no data to betransmitted by the UE to the base station.